with 
Numero as ( 
select 152 N from dual 
union all select 14587 from dual 
union all select 14 from dual 
union all select 7816 from dual 
union all select 174 from dual 
union all select 458 from dual 
union all select 17548987 from dual 
union all select 458157 from dual 
union all select 14850 from dual 
union all select 21410 from dual 
union all select 100 from dual 
union all select 457500 from dual 
union all select 82100 from dual 
) 
, 
PreProcesado1 as ( 
select   N 
       , floor(mod(N, 1000000) / 100000) MillarCentenas 
       , floor(mod(N, 100000) / 10000) MillarDecenas 
       , floor(mod(N, 10000) / 1000) MillarUnidades 
       , floor(mod(N, 1000) / 100) Centenas 
       , floor(mod(N, 100) / 10) Decenas 
       , floor(mod(N, 10)) Unidades 
  from Numero 
) 
select   N 
       ,  case Centenas 
            when 0 then '' 
            when 1 then case when Decenas = 0 and Unidades = 0 then 'cien ' else 'ciento ' end 
            when 2 then 'doscientos ' 
            when 3 then 'trescientos ' 
            when 4 then 'cuatrocientos ' 
            when 5 then 'quinientos ' 
            when 6 then 'seiscientos ' 
            when 7 then 'setecientos ' 
            when 8 then 'ochocientos ' 
            when 9 then 'novecientos ' 
          end 
       || case Decenas 
            when 0 then '' 
            when 2 then 'veinte ' 
            when 3 then 'treinta ' 
            when 4 then 'cuarenta ' 
            when 5 then 'cincuenta ' 
            when 6 then 'sesenta ' 
            when 7 then 'setenta ' 
            when 8 then 'ochenta ' 
            when 9 then 'noventa ' 
            when 1 then 
              case Unidades 
                when 0 then 'diez ' 
                when 1 then 'once ' 
                when 2 then 'doce ' 
                when 3 then 'trece ' 
                when 4 then 'catorce ' 
                when 5 then 'quince ' 
                else 'dieci' 
              end 
          end 
       || case when Decenas > 1 and Unidades <> 0 then 'y ' else '' end 
       || case  
            when Decenas = 1 and Unidades < 6 then ''  
            else 
              case Unidades  
                when 0 then '' 
                when 1 then 'uno' 
                when 2 then 'dos' 
                when 3 then 'tres' 
                when 4 then 'cuatro' 
                when 5 then 'cinco' 
                when 6 then 'seis' 
                when 7 then 'siete' 
                when 8 then 'ocho' 
                when 9 then 'nueve' 
              end 
            end  
       NumeroEnLetras 
  from PreProcesado1